A number of prior art systems exist for applying labels to containers, either continuous roll fed labels or cut and stack labels.
Apparatus and method commonly employed to apply sheet fed, cut and stack labels (i.e., labels that have been cut offline and thereafter retained in a stack within a dispensing magazine) to containers, such as bottles, selectively apply an adhesive to the lowermost label in the dispensing magazine while, at the same time, removing the lowermost label from the stack for subsequent application to a container. Such systems have employed cold glue adhesive, which is water soluble, and sometimes a hot melt adhesive. In addition, radiation curable adhesives are being utilized by applicant's assignee, as disclosed in the various related applications and issued patents identified earlier in this application.
In apparatus and method commonly employed for directing, in sequence, individual sheet fed, cut and stack labels from a dispensing magazine, adhesive initially is applied to a transfer pad that subsequently engages a confronting surface of the lowermost label in the magazine for both applying the adhesive to the label and removing the label from the stack. The adhesive is applied substantially uniformly over the confronting surface of the label, except in regions corresponding to cut out sections of the transfer pad. These cut out sections are provided to permit a label carried by the transfer pad to be engaged in the region of the cutouts by gripper fingers of a subsequent transfer mechanism that conveys the labels to their point of application to the containers.
Although equipment employing a transfer mechanism with the above-described fingers has been commercially utilized for years, a problem does exist in achieving uniformity in the adhesive layer, particularly in the regions of the label corresponding to the cutout sections of the transfer pad. Non-uniformity in the adhesive layer creates visual defects when the label is applied to a container. These visual defects are most pronounced in transparent labels, where bubbles and voids are readily apparent by visual inspection through the label. Moreover these visual defects can present a problem even in opaque labels, when the labels are reverse printed on the adhesive side for viewing through a container that includes a relatively clear fluid (e.g., beer) in it.
Although cold glue adhesives and radiation curable adhesives have been applied in a manner to permit them to cold flow into the regions of the label initially devoid of adhesive, this flow has not always been uniform, still resulting in the formation of bubbles, striations and other imperfections in the adhesive layer that are visually discernable and aesthetically unappealing.
Therefore, a need exists to further eliminate visual defects in labels created by the omission of adhesive from regions of the label facestock at such time as the adhesive initially is applied to said facestock. It is to such improvements that the present invention relates.